Sunday, August 24, 2003

What's Wrong with RDF/XML?

"Reported RDF/XML problems:
1. One cannot tell an RDF node element/property element by simple inspection of the element in question without knowing the ``striping'' (after Brickley[10]).
2. The frame-style approach does not clearly match the triples in the RDF graph.
3. There are excessive choices in choosing how to write RDF/XML.
4. Elements, attributes and attribute values are used for the same purposes, for example, encoding a URI.
5. The way that XML QNames are used does not constrain the elements and attributes that can appear in RDF/XML.
6. The unconstrained syntax cannot be described completely with XML schema languages such as DTDs and W3C XML Schema.
7. RDF/XML does not use W3C XML Schema datatypes.
8. The syntax is not easy to use with XML technologies such as XSLT, XQuery and other XML tools.
9. It is impossible to embed in XHTML while retaining DTD validation.
10. The syntax is incapable of encoding all legal RDF graphs.
11. In particular, certain graphs with blank nodes cannot be serialised.
12. It uses both namespaced and non-namespaced XML attributes for syntax terms.
13. It is hard to emit human-readable RDF/XML from an RDF graph due to the range of choices (after Carroll[11]).
14. Various aesthetic comments were levelled such as such as being ``ugly''."